Effects of incorporation of immunoglobulin G and complement component C1q on uptake and degradation of Alzheimer's disease amyloid fibrils by microglia Academic Article uri icon

Overview

MeSH Major

  • Alzheimer Disease
  • Amyloid
  • Complement C1q
  • Immunoglobulin G
  • Microglia

abstract

  • Microglia are macrophage-like immune system cells found in the brain. They are associated with Alzheimer's Disease plaques, which contain fibrillar beta-amyloid (fAbeta) and other components such as complement proteins. We have shown previously that murine microglia bind and internalize fAbeta microaggregates via the type A scavenger receptor, but degradation of internalized fAbeta is significantly slower than normal degradation. In this study, we compared internalization by microglia of fAbeta microaggregates to that of anti-Abeta-antibody-coated fAbeta (IgG-fAbeta) microaggregates and found that the uptake of the latter is increased by about 1.5-fold versus unmodified fAbeta. The endocytic trafficking of IgG-fAbeta is similar to that of fAbeta microaggregates, following an endosomal/lysosomal pathway. We also compared the internalization of fAbeta microaggregates to that of complement protein, C1q-coated fAbeta microaggregates, and found that the levels of uptake are also increased by about 1.5-fold. Rates of degradation of both types of modified fAbeta microaggregates are unchanged compared with unmodified fAbeta microaggregates. We demonstrated by blocking studies that internalization of IgG-fAbeta is mediated by Fc receptors. These data suggest that, in vivo, several different microglial receptors may play a part in internalizing fAbeta, but the involvement of other receptors may not increase the degradation of fAbeta.

publication date

  • June 2, 2000

Research

keywords

  • Academic Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1074/jbc.M000937200

PubMed ID

  • 10747968

Additional Document Info

start page

  • 16941

end page

  • 7

volume

  • 275

number

  • 22